Type hints for multifilesystem

radicale/storage/multifilesystem/meta.py

@@ -18,18 +18,33 @@
 
 import json
 import os
+from typing import Mapping, Optional, TextIO, Union, cast, overload
 
 import radicale.item as radicale_item
+from radicale.storage import multifilesystem
+from radicale.storage.multifilesystem.base import CollectionBase
 
 
-class CollectionMetaMixin:
-    def __init__(self):
-        super().__init__()
+class CollectionPartMeta(CollectionBase):
+
+    _meta_cache: Optional[Mapping[str, str]]
+    _props_path: str
+
+    def __init__(self, storage_: "multifilesystem.Storage", path: str,
+                 filesystem_path: Optional[str] = None) -> None:
+        super().__init__(storage_, path, filesystem_path)
         self._meta_cache = None
         self._props_path = os.path.join(
             self._filesystem_path, ".Radicale.props")
 
-    def get_meta(self, key=None):
+    @overload
+    def get_meta(self, key: None = None) -> Mapping[str, str]: ...
+
+    @overload
+    def get_meta(self, key: str) -> Optional[str]: ...
+
+    def get_meta(self, key: Optional[str] = None) -> Union[Mapping[str, str],
+                                                           Optional[str]]:
         # reuse cached value if the storage is read-only
         if self._storage._lock.locked == "w" or self._meta_cache is None:
             try:
@@ -45,6 +60,7 @@ class CollectionMetaMixin:
                                    "%r: %s" % (self.path, e)) from e
         return self._meta_cache if key is None else self._meta_cache.get(key)
 
-    def set_meta(self, props):
-        with self._atomic_write(self._props_path, "w") as f:
+    def set_meta(self, props: Mapping[str, str]) -> None:
+        with self._atomic_write(self._props_path, "w") as fo:
+            f = cast(TextIO, fo)
             json.dump(props, f, sort_keys=True)